package edu.cmu.ark;
/*

   Porter stemmer in Java. The original paper is in

       Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
       no. 3, pp 130-137,

   See also http://www.tartarus.org/~martin/PorterStemmer

   History:

   Release 1

   Bug 1 (reported by Gonzalo Parra 16/10/99) fixed as marked below.
   The words 'aed', 'eed', 'oed' leave k at 'a' for step 3, and b[k-1]
   is then out outside the bounds of b.

   Release 2

   Similarly,

   Bug 2 (reported by Steve Dyrdahl 22/2/00) fixed as marked below.
   'ion' by itself leaves j = -1 in the test for 'ion' in step 5, and
   b[j] is then outside the bounds of b.

   Release 3

   Considerably revised 4/9/00 in the light of many helpful suggestions
   from Brian Goetz of Quiotix Corporation (brian@quiotix.com).

   Release 4

   Slightly modified August, 2010 by Michael Heilman (mheilman@cmu.edu)
   to improve the API.

 */

/**
 * 
 */


import java.io.*;

/**
 * Stemmer, implementing the Porter Stemming Algorithm
 *
 * The Stemmer class transforms a word into its root form.  The input
 * word can be provided a character at time (by calling add()), or at once
 * by calling one of the various stem(something) methods.
 */

public class PorterStemmer
{  private char[] b;
private int i,     /* offset into b */
i_end, /* offset to end of stemmed word */
j, k;
private static final int INC = 50;
/* unit of size whereby b is increased */
private PorterStemmer()
{  b = new char[INC];
i = 0;
i_end = 0;
}

/**
 * Add a character to the word being stemmed.  When you are finished
 * adding characters, you can call stem(void) to stem the word.
 */

public void add(char ch)
{  if (i == b.length)
{  char[] new_b = new char[i+INC];
for (int c = 0; c < i; c++) new_b[c] = b[c];
b = new_b;
}
b[i++] = ch;
}


/** Adds wLen characters to the word being stemmed contained in a portion
 * of a char[] array. This is like repeated calls of add(char ch), but
 * faster.
 */

public void add(char[] w, int wLen)
{  if (i+wLen >= b.length)
{  char[] new_b = new char[i+wLen+INC];
for (int c = 0; c < i; c++) new_b[c] = b[c];
b = new_b;
}
for (int c = 0; c < wLen; c++) b[i++] = w[c];
}

/**
 * After a word has been stemmed, it can be retrieved by toString(),
 * or a reference to the internal buffer can be retrieved by getResultBuffer
 * and getResultLength (which is generally more efficient.)
 */
public String toString() { return new String(b,0,i_end); }

/**
 * Returns the length of the word resulting from the stemming process.
 */
public int getResultLength() { return i_end; }

/**
 * Returns a reference to a character buffer containing the results of
 * the stemming process.  You also need to consult getResultLength()
 * to determine the length of the result.
 */
public char[] getResultBuffer() { return b; }

/* cons(i) is true <=> b[i] is a consonant. */

private final boolean cons(int i)
{  switch (b[i])
	{  case 'a': case 'e': case 'i': case 'o': case 'u': return false;
	case 'y': return (i==0) ? true : !cons(i-1);
	default: return true;
	}
}

/* m() measures the number of consonant sequences between 0 and j. if c is
      a consonant sequence and v a vowel sequence, and <..> indicates arbitrary
      presence,

         <c><v>       gives 0
         <c>vc<v>     gives 1
         <c>vcvc<v>   gives 2
         <c>vcvcvc<v> gives 3
         ....
 */

private final int m()
{  int n = 0;
int i = 0;
while(true)
{  if (i > j) return n;
if (! cons(i)) break; i++;
}
i++;
while(true)
{  while(true)
{  if (i > j) return n;
if (cons(i)) break;
i++;
}
i++;
n++;
while(true)
{  if (i > j) return n;
if (! cons(i)) break;
i++;
}
i++;
}
}

/* vowelinstem() is true <=> 0,...j contains a vowel */

private final boolean vowelinstem()
{  int i; for (i = 0; i <= j; i++) if (! cons(i)) return true;
return false;
}

/* doublec(j) is true <=> j,(j-1) contain a double consonant. */

private final boolean doublec(int j)
{  if (j < 1) return false;
if (b[j] != b[j-1]) return false;
return cons(j);
}

/* cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
      and also if the second c is not w,x or y. this is used when trying to
      restore an e at the end of a short word. e.g.

         cav(e), lov(e), hop(e), crim(e), but
         snow, box, tray.

 */

private final boolean cvc(int i)
{  if (i < 2 || !cons(i) || cons(i-1) || !cons(i-2)) return false;
{  int ch = b[i];
if (ch == 'w' || ch == 'x' || ch == 'y') return false;
}
return true;
}

private final boolean ends(String s)
{  int l = s.length();
int o = k-l+1;
if (o < 0) return false;
for (int i = 0; i < l; i++) if (b[o+i] != s.charAt(i)) return false;
j = k-l;
return true;
}

/* setto(s) sets (j+1),...k to the characters in the string s, readjusting
      k. */

private final void setto(String s)
{  int l = s.length();
int o = j+1;
for (int i = 0; i < l; i++) b[o+i] = s.charAt(i);
k = j+l;
}

/* r(s) is used further down. */

private final void r(String s) { if (m() > 0) setto(s); }

/* step1() gets rid of plurals and -ed or -ing. e.g.

          caresses  ->  caress
          ponies    ->  poni
          ties      ->  ti
          caress    ->  caress
          cats      ->  cat

          feed      ->  feed
          agreed    ->  agree
          disabled  ->  disable

          matting   ->  mat
          mating    ->  mate
          meeting   ->  meet
          milling   ->  mill
          messing   ->  mess

          meetings  ->  meet

 */

private final void step1()
{  if (b[k] == 's')
{  if (ends("sses")) k -= 2; else
	if (ends("ies")) setto("i"); else
		if (b[k-1] != 's') k--;
}
if (ends("eed")) { if (m() > 0) k--; } else
	if ((ends("ed") || ends("ing")) && vowelinstem())
	{  k = j;
	if (ends("at")) setto("ate"); else
		if (ends("bl")) setto("ble"); else
			if (ends("iz")) setto("ize"); else
				if (doublec(k))
				{  k--;
				{  int ch = b[k];
				if (ch == 'l' || ch == 's' || ch == 'z') k++;
				}
				}
				else if (m() == 1 && cvc(k)) setto("e");
	}
}

/* step2() turns terminal y to i when there is another vowel in the stem. */

private final void step2() { if (ends("y") && vowelinstem()) b[k] = 'i'; }

/* step3() maps double suffices to single ones. so -ization ( = -ize plus
      -ation) maps to -ize etc. note that the string before the suffix must give
      m() > 0. */

private final void step3() { if (k == 0) return; /* For Bug 1 */ switch (b[k-1])
{
case 'a': if (ends("ational")) { r("ate"); break; }
if (ends("tional")) { r("tion"); break; }
break;
case 'c': if (ends("enci")) { r("ence"); break; }
if (ends("anci")) { r("ance"); break; }
break;
case 'e': if (ends("izer")) { r("ize"); break; }
break;
case 'l': if (ends("bli")) { r("ble"); break; }
if (ends("alli")) { r("al"); break; }
if (ends("entli")) { r("ent"); break; }
if (ends("eli")) { r("e"); break; }
if (ends("ousli")) { r("ous"); break; }
break;
case 'o': if (ends("ization")) { r("ize"); break; }
if (ends("ation")) { r("ate"); break; }
if (ends("ator")) { r("ate"); break; }
break;
case 's': if (ends("alism")) { r("al"); break; }
if (ends("iveness")) { r("ive"); break; }
if (ends("fulness")) { r("ful"); break; }
if (ends("ousness")) { r("ous"); break; }
break;
case 't': if (ends("aliti")) { r("al"); break; }
if (ends("iviti")) { r("ive"); break; }
if (ends("biliti")) { r("ble"); break; }
break;
case 'g': if (ends("logi")) { r("log"); break; }
} }

/* step4() deals with -ic-, -full, -ness etc. similar strategy to step3. */

private final void step4() { switch (b[k])
	{
	case 'e': if (ends("icate")) { r("ic"); break; }
	if (ends("ative")) { r(""); break; }
	if (ends("alize")) { r("al"); break; }
	break;
	case 'i': if (ends("iciti")) { r("ic"); break; }
	break;
	case 'l': if (ends("ical")) { r("ic"); break; }
	if (ends("ful")) { r(""); break; }
	break;
	case 's': if (ends("ness")) { r(""); break; }
	break;
	} }

/* step5() takes off -ant, -ence etc., in context <c>vcvc<v>. */

private final void step5()
{   if (k == 0) return; /* for Bug 1 */ switch (b[k-1])
{  case 'a': if (ends("al")) break; return;
case 'c': if (ends("ance")) break;
if (ends("ence")) break; return;
case 'e': if (ends("er")) break; return;
case 'i': if (ends("ic")) break; return;
case 'l': if (ends("able")) break;
if (ends("ible")) break; return;
case 'n': if (ends("ant")) break;
if (ends("ement")) break;
if (ends("ment")) break;
/* element etc. not stripped before the m */
if (ends("ent")) break; return;
case 'o': if (ends("ion") && j >= 0 && (b[j] == 's' || b[j] == 't')) break;
/* j >= 0 fixes Bug 2 */
if (ends("ou")) break; return;
/* takes care of -ous */
case 's': if (ends("ism")) break; return;
case 't': if (ends("ate")) break;
if (ends("iti")) break; return;
case 'u': if (ends("ous")) break; return;
case 'v': if (ends("ive")) break; return;
case 'z': if (ends("ize")) break; return;
default: return;
}
if (m() > 1) k = j;
}

public String stem(String w){
	String lowercased = w.toLowerCase();

	for(int i=0; i<lowercased.length(); i++){
		add(lowercased.charAt(i));
	}

	stemHelper();
	return toString();
}


/* step6() removes a final -e if m() > 1. */

private final void step6()
{  j = k;
if (b[k] == 'e')
{  int a = m();
if (a > 1 || a == 1 && !cvc(k-1)) k--;
}
if (b[k] == 'l' && doublec(k) && m() > 1) k--;
}


public static PorterStemmer getInstance(){
	if(instance == null){
		instance = new PorterStemmer();
	}
	return instance;
}


/** Stem the word placed into the Stemmer buffer through calls to add().
 * Returns true if the stemming process resulted in a word different
 * from the input.  You can retrieve the result with
 * getResultLength()/getResultBuffer() or toString().
 */
private void stemHelper()
{  k = i - 1;
if (k > 1) { step1(); step2(); step3(); step4(); step5(); step6(); }
i_end = k+1; i = 0;
}




/** Test program for demonstrating the Stemmer.  It reads text from a
 * a list of files, stems each word, and writes the result to standard
 * output. Note that the word stemmed is expected to be in lower case:
 * forcing lower case must be done outside the Stemmer class.
 * Usage: Stemmer file-name file-name ...
 */
public static void main(String[] args) throws IOException
{
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String buf;
	String [] parts;

	while((buf = br.readLine()) != null){
		parts = buf.split("\\b+");
		
		for(int i=0; i<parts.length; i++){
			System.out.print(PorterStemmer.getInstance().stem(parts[i])+" ");
		}

		System.out.println();
	}

}

private static PorterStemmer instance;
}
